In recent years, there is an automobiles that is called a welfare vehicle in which a wheelchair-sitting person sitting in a wheelchair can be loaded with the wheelchair. Such a welfare vehicle has a wheelchair lifting and transferring device in order to load the wheelchair-sitting person therein with the wheelchair (Japanese Laid-Open Patent Application No. 2005-304767 described below). The wheelchair lifting and transferring device generally has a platform on which the wheelchair is to be placed, and a lifting and transferring mechanism that is configured to lift-transfer this platform from a vehicle exterior to a vehicle interior. The wheelchair lifting and transferring device is configured to lower the platform onto a road surface in the vehicle exterior. The wheelchair-sitting person is placed on the platform lowered onto the road surface with the wheelchair. The platform on which the wheelchair placed is transferred into the vehicle interior by the lifting and transferring mechanism, whereby the wheelchair-sitting person is loaded in the vehicle with the wheelchair.
Like an ordinary passenger, such a wheelchair-sitting person thus loaded in the vehicle is also required to be seat-belted. In this connection, the wheelchair lifting and transferring device disclosed in Japanese Laid-Open Patent Application No. 2005-304767 is provided with a seat-belt device having a wrap belt that is capable of constraining the waist of the wheelchair-sitting person and a shoulder belt that is capable constraining the upper half of his/her body from the shoulder to the waist.
According to this seatbelt device, it is possible to constrain the body of the wheelchair-sitting person by the wrap belt and the shoulder belt. Further, in order to apply the wrap belt and the shoulder belt to such a person, an application operation is performed with attention to the following points. That is, when the wrap belt and the shoulder belt is applied to the person, it is necessary to additionally thread the belts under an armrest of the wheelchair and between spokes of wheels of the wheelchair such that the belts may reliably contact the body of the wheelchair-sitting person. However, it is difficult for the wheelchair-sitting person to perform a threading operation of the belts. Therefore, such an operation may generally be performed by a person assisting loading of the wheelchair-sitting person (which may be hereinafter referred to as a loading assistant).